NIC Barber Written (Theory) ExamFacial and Skin Care ServicesHard
A client with Fitzpatrick skin type IV is requesting a chemical exfoliation treatment. Which of the following acids, known for its larger molecular size and gentler action on the skin's surface, would be the safest choice to minimize the risk of post-inflammatory hyperpigmentation (PIH)?
- ASalicylic acid
- BGlycolic acid
- CLactic acid
- DTrichloroacetic acid (TCA)
Show answer & explanationAnswer & explanation
Correct answer: C. Lactic acid
Lactic acid has a larger molecular size than glycolic acid, making it penetrate more slowly and superficially. This gentler action, combined with its hydrating properties, makes it a safer choice for darker skin types (Fitzpatrick IV-VI) to reduce the risk of PIH compared to more aggressive acids.
Why the other options are wrong
- A. Salicylic acid is a BHA, oil-soluble, and effective for acne, but doesn't specifically address the molecular size/gentleness for PIH risk in Fitzpatrick IV as directly as lactic acid.
- B. Glycolic acid has the smallest molecular size among AHAs, allowing for deeper penetration and higher risk of irritation and PIH in darker skin types.
- D. TCA is a much stronger acid used for medium to deep peels, posing a significant risk of PIH and other complications for Fitzpatrick IV skin if not used with extreme caution and expertise.
Lactic Acid (for PIH prevention)
An Alpha Hydroxy Acid (AHA) with a larger molecular structure, making it a gentler exfoliant suitable for sensitive or darker skin types prone to post-inflammatory hyperpigmentation.
- Derived from milk, known for hydrating properties.
- Larger molecular size compared to glycolic acid results in slower, more superficial penetration.
- Minimizes irritation and risk of PIH, especially in Fitzpatrick skin types IV-VI.
Memory trick: Lactic is Larger, Less Likely to Leave Marks (PIH) on darker skin.